This invention relates to a radio exchanging station carrying out a call control in a plurality of processors and, more particularly, to a call distributing method for carrying out distribution for traffic of the radio exchanging station to avoid a congestion state in each processor.
A conventional radio exchanging station comprises a plurality of call control processors and a call control monitoring processor. The call control monitoring processor is called a congestion control processor. In a case where the radio exchanging station carries out call control for the call control processors, a call distribution method is carried out as follows. That is, the call control monitoring processor (the congestion control processor) monitors congestion states of the respective call control processors. When a particular call control processor is put into the congestion state, a request of the call control from the call control monitoring processor to the particular call control processor is regulated. Accordingly, the conventional call distributing method is disadvantageous in that call distribution to the call control processor in question increases and it results in adversely effecting other call control processors. Accordingly, the conventional radio exchanging station may carry out an unstable call control.
Various prior arts related to this invention are already known. By way of example, Japanese Unexamined Patent Publication (JP-A) of Tokkai No. Hei 7-298,340 or JP-A 7-298340 discloses a mobile communication system and a mobile station, which are capable of enabling first through fourth items, i.e., the setting of whether a speech channel is switched or not by a mobile station user, the early detection of an illegal mobile station, the avoidance of convergence of call control processing at a base station control station, and the avoidance of convergence of a simultaneous call channel. According to JP-A 7-298340, for the first item, a mobile station is provided with an arrangement which informs a user that a speech channel switching factor is detected on a mobile network side and a switch which enables the user to select whether a telephone call can be selected, thereby enabling the intention of the user to be transmitted to the network side. For the second item, the cumulative telephone charge is totalized individually on the network side and mobile station side and compared with each other to find the illegal mobile station. For the third item, the number of base stations controlled by the base station control station is varied dynamically in real time according to the convergence state. For the fourth item, the number of radio zones constituting position registration areas is varied in real time according to the load state of call processing, etc., to places peripheral position registration areas in partial charge of a load.
Japanese Unexamined Patent Publication (JP-A) of Tokkai No. Hei 8-287,032 or JP-A 8-287032 discloses a communication management system for multi-processor system, which is capable of reliving a congestion state by the mutual communication processing of a plurality of processors by providing each processor with a recognizing arrangement allowing the processor to recognize the congestion states of all processors. According to JP-A 8-287032, the communication management system is provided with a plurality of call processing processors for mainly controlling the exchange processing of a private branch exchange (PBX) and respective processors are mutually connected through communication lines so as to execute mutual communication. Each processor is provided with a recognizing arrangement allowing the processor to recognize the congestion states of all processors. The recognizing arrangement mutually transmits/receives congestion state information to/from recognizing arrangements in other processors through communication lines. Thereby each processor can recognize the congestion states of other processors, and when a certain processor in the system reaches a congestion state, the congestion state can be relieved by the mutual communication processing of respective processors before system transmission regulation is generated from a management processor.
Japanese Unexamined Patent, Publication (JP-A) of Tokkai No. Hei 10-65,728 or JP-A 10-65728 discloses a distribution processor-type data exchange where the processing ability of a whole system is improved. According to JP-A 10-65728, the exchange is provided with a node control processor (NCP) and a plurality of line containing processors (LCP) for executing the routing processing of a call. The node control processor controls the utilizing ratio of CPU of whole line containing processors and the processor number of the lowest CPU utilizing ratio is reported to whole line containing processors by multi-address communication. In the meantime, when a processing request is received, respective line containing processors shift the processing to the processor with the lower CPU utilizing ratio when the CPU utilizing ratio of itself is high.
Japanese Unexamined Patent Publication (JP-A) of Tokkai No. Hei 5-89,055 or JP-A 5-89055 discloses a packet exchange control system in a multi processor system, which is capable of performing the control of a data transfer phase by a multi processor system in one processor. According to JP-A 5-89055, by the transmitting and receiving of a route selection information (including transmitting side information and master deciding information) signal from a transmitting side function block at the time of setting a call and a connection completion (including transmitting side control request and receiving side information) signal from a receiving side function block, the transmitting side is decided to be a master. Subsequently, by making possible the transmitting and receiving of a signal of slave side receiving side function block at the time of a data transfer phase and a transmitting side function block, the control of a data transmitting requesting signal from both transmitting side and receiving side is performed at the transmitting side function block (master side).
It is therefore an object of this invention to provide a call distribution method which is capable of decreasing distribution for call processing execution processors in a selection processing execution processor.
It is another object of this invention to provide a call distribution method of the type described, which has no adverse effect on other call processing execution processors.
It is still another object of this invention to provide a call distribution method of the type described, which is capable of continuing a stable call processing operation.
Other objects of this invention will become clear as the description proceeds.
On describing the gist of an aspect of this invention, it is necessary to be understood that a method is for distributing calls in a radio exchanging station for use in a mobile communication system. The radio exchanging station comprises a selection processing execution processor and first through N-th call processing execution processors, where N represents a positive integer which is not less than two.
According to the aspect of this invention, an n-th call processing execution processor periodically delivers, to the selection processing execution processor, an n-th use condition signal indicative of an n-th use condition of an n-th radio resource managed by the n-th call processing execution processor and an n-th load condition signal indicative of an n-th load condition of the n-th call processing execution processor, where n represents each of 1 through N. On the basis of first through N-th use conditions and first through N-th load conditions, the selection processing execution processor determines first through N-th call reception permissible numbers for distributing to the first through the N-th call processing execution processors, respectively. In addition, the radio exchanging station may comprise only one call processing execution processor in lieu of a plurality of call processing execution stations.